The present disclosure relates to a portable breathing apparatus. More specifically, the present disclosure relates to portable, surface rebreather breathing apparatus having a cooling system.
A rebreather is a closed loop breathing apparatus. A user exhales into the rebreather and the exhalant gas stream enters a scrubber bed. The scrubber bed chemically absorbs carbon dioxide (CO2) from the exhalant gas stream but allows the other components of the exhalant gas stream to pass through. Oxygen is added to the scrubbed exhalant gas stream to make up for any oxygen absorbed by the user during rebreather use. The O2 enriched scrubbed exhalant gas continues through the apparatus to be inhaled by the user.
The scrubbing of the CO2 in the scrubber bed creates an exothermic reaction, i.e., a temperature change. In some cases, the temperature of the scrubber bed can increase up to about 150 degrees Fahrenheit (about 66 degrees Celsius). Because the rebreather apparatus is a closed loop system, the temperature increase of the scrubber bed increases the temperature of the scrubbed exhalant gas. A temperature increase in the scrubbed exhalant gas can cause the user discomfort. Some surface rebreathers use ice blocks to cool the scrubbed exhalant gas to alleviate any discomfort for the user.
Accordingly, there exists a need for a more efficient cooling system in a closed-loop surface rebreather apparatus that also allows for multiple missions.